Difference between revisions of "Lateral Boundary Conditions"
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[[Image:LBC_indices.png|250px]] | [[Image:LBC_indices.png|250px]] | ||
For example, | For example, the free-surface gradient boundary conditions are specified as:<div class="box"> [[Variables#LBC|LBC]]([[Variables#iwest|iwest]], [[Variables#isFsur|isFsur]], ng) % gradient<br /> [[Variables#LBC|LBC]]([[Variables#ieast|ieast]], [[Variables#isFsur|isFsur]], ng) % gradient<br /> [[Variables#LBC|LBC]]([[Variables#isouth|isouth]], [[Variables#isFsur|isFsur]], ng) % gradient<br /> [[Variables#LBC|LBC]]([[Variables#inorth|inorth]], [[Variables#isFsur|isFsur]], ng) % gradient</div>The structure is declared in [[mod_param.F]] as:<div class="box"> integer :: [[Variables#nLBCvar|nLBCvar]]<br /><br /> TYPE T_LBC<br /> logical :: acquire ! process lateral boundary data<br /><br /> logical :: Chapman<br /> logical :: clamped<br /> logical :: closed<br /> logical :: Flather<br /> logical :: gradient<br /> logical :: nested<br /> logical :: nudging<br /> logical :: periodic<br /> logical :: radiation<br /> logical :: reduced<br /> END TYPE T_LBC<br /><br /> TYPE (T_LBC), allocatable :: [[Variables#LBC|LBC]](:,:,:)<br /><br /> TYPE (T_LBC), allocatable :: [[Variables#ad_LBC|ad_LBC]](:,:,:)<br /> TYPE (T_LBC), allocatable :: [[Variables#tl_LBC|tl_LBC]](:,:,:) </div> | ||
Revision as of 14:20, 13 September 2011
The lateral boundary conditions are specified by logical switches to facilitate applications with nested grids. It also allows to set different boundary conditions between the nonlinear model and the adjoint/tangent models. In addition, we can have different boundary conditions between active and passive tracers. The LBC structure is allocated as:
where 1:4 are the numbered boundary edges, nLBCvar is the number of LBC state variables, and Ngrids is the number of nested grids. The boundary order is: 1=west, 2=south, 3=east, and 4=north. That is, anticlockwise starting at the western boundary.
For example, the free-surface gradient boundary conditions are specified as:
LBC(ieast, isFsur, ng) % gradient
LBC(isouth, isFsur, ng) % gradient
LBC(inorth, isFsur, ng) % gradient
The structure is declared in mod_param.F as:
TYPE T_LBC
logical :: acquire ! process lateral boundary data
logical :: Chapman
logical :: clamped
logical :: closed
logical :: Flather
logical :: gradient
logical :: nested
logical :: nudging
logical :: periodic
logical :: radiation
logical :: reduced
END TYPE T_LBC
TYPE (T_LBC), allocatable :: LBC(:,:,:)
TYPE (T_LBC), allocatable :: ad_LBC(:,:,:)
TYPE (T_LBC), allocatable :: tl_LBC(:,:,:)
Conversion Tables
Starting with ROMS version 3.6, the CPP options for lateral boundary conditions (user defined and internal) are deprecated and replaced with logical switches that are specified in the standard input files. The following tables show the conversion from CPP options to logical switches for each state variable using the LBC structure:
TKE mixing | |
---|---|
CPP | Logical Switch, IF (...) THEN |
WESTERN_WALL | LBC(iwest, isMtke, ng) % closed |
EASTERN_WALL | LBC(ieast, isMtke, ng) % closed |
SOUTHERN_WALL | LBC(isouth, isMtke, ng) % closed |
NORTHERN_WALL | LBC(inorth, isMtke, ng) % closed |
WEST_KGRADIENT | LBC(iwest, isMtke, ng) % gradient |
EAST_KGRADIENT | LBC(ieast, isMtke, ng) % gradient |
SOUTH_KGRADIENT | LBC(isouth, isMtke, ng) % gradient |
NORTH_KGRADIENT | LBC(inorth, isMtke, ng) % gradient |
EW_PERIODIC | EWperiodic(ng) LBC(iwest, isMtke, ng) % periodic LBC(ieast, isMtke, ng) % periodic |
NS_PERIODIC | NSperiodic(ng) LBC(isouth, isMtke, ng) % periodic LBC(inorth, isMtke, ng) % periodic |
WEST_KRADIATION | LBC(iwest, isMtke, ng) % radiation |
EAST_KRADIATION | LBC(ieast, isMtke, ng) % radiation |
SOUTH_KRADIATION | LBC(isouth, isMtke, ng) % radiation |
NORTH_KRADIATION | LBC(inorth, isMtke, ng) % radiation |
Starting with ROMS version 3.6, the CPP options for volume conservation are deprecated and replaced with logical switches that are specified in the ocean.in file. The following tables show the conversion from CPP options to logical switches:
Volume Conservation | |
---|---|
CPP | Logical Switch, IF (...) THEN |
WEST_VOLCONS | VolCons(iwest, ng) |
EAST_VOLCONS | VolCons(ieast, ng) |
SOUTH_VOLCONS | VolCons(isouth, ng) |
NORTH_VOLCONS | VolCons(inorth, ng) |